Al-Mg-Sc合金热压缩变形的流变应力行为

采用热模拟试验对1种Al-Mg-Sc合金进行等温热压缩实验,研究该合金在变形温度为300～450℃,应变速率0.001～1 s-1条件下的热压缩变形流变应力行为.结果表明:该Al-Mg-Sc合金在变形温度为300℃,应变速率0.01～1 s-1的条件下,流变应力开始随应变增加而增大,达到峰值后趋于平稳,表现出动态回复特征;而在其他条件下,应力达到峰值后随应变的增加而逐渐下降,表现出动态再结晶特征.应变速率和流变应力之间满足指数关系,温度和流变应力之间满足Arrhenius关系,通过线性回归分析计算出该材料的应变硬化指数n以及变形激活能Q,获得该铝合金高温条件下的流变应力本构方程.     

铝合金热变形的本构模型研究

利用Gleeble-1500热模拟机,研究轧制态6016铝合金在变形温度为300～500℃,应变速率为0.1～10 s-1以及真应变为0～0.8时高温单道次压缩过程中热变形流变应力行为.研究结果表明:6016铝合金在高温单道次压缩下的热变形经历了从应变硬化阶段过渡到稳态变形阶段的过程,其软化机制主要为动态回复;据流变应力指数函数中系数A和β与应变的关系,建立Zener-Hollomon参数的指数关系本构方程;计算所得的温升修正值与实测值较吻合.     

Mg-5.3Zn-0.8Zr镁合金高温变形行为的热模拟研究

采用Gieeble-1500热模拟试验机进行压缩实验,研究Mg-5.3Zn-0.8Zr镁合金在变形温度为473～723 K、应变速率为0.01～1.00s-1的变形行为.分析合金流变应力与应变速率、变形温度之间的关系,计算高N(573～723 K)下合金变形时的应力指数和变形激活能,并采用Zener-Hollomon参数法构建该合金高温塑性变形的本构关系.研究结果表明:在实验变形条件范围内,合金的真应力-真应变曲线为动态再结晶型;在573～723 K,应力指数随着变形温度升高而增加,而且增加的幅度逐渐增大,变形激活能随着变形温度和应变速率的改变而发生变化.     

Ti45Al8Nb2Mn0.2B铸造合金高温形变行为

Ti45Al8Nb2Mn0.2B铸造合金在900～1200℃温度范围,1～10-3/s应变速率条件下进行压缩实验,研究其变形特点以及组织变化.结果发现,形变过程中合金的真应力-真应变曲线上存在一个应力峰值,随后流变应力随着应变量的增加逐渐下降并趋于稳态流变.降低温度和提高应变速率都使合金的应力峰值增加.在实验温度范围内合金的应变速率敏感系数为0.10～0.24;在高温形变过程中发生动态再结晶,合金的组织得到明显细化.再结晶晶粒尺寸随温度的降低和应变速率的增加而减小,也就是随Zener-Hollomonc参数的增加而减小;升高形变温度和降低应变速率均促进再结晶过程.     

N12160高温合金热压缩变形行为和加工图

该文所研究的N12160合金等温热压实验是在Gleeble-3500热模拟试验机上进行的。获得了N12160合金在应变速率为0.01～5s~(-1)、变形温度为950℃～1200℃条件下的真应力-真应变曲线。该文采用Arrhenius方程描述了该合金的流变应力行为,同时基于动态材料模型(DMM)建立了N12160合金在不同应变量下的热加工图研究。结果表明:在热压缩变形过程中,流变应力随应变速率的增加而增加,随变形温度的增加而减小。根据热加工图以及微观组织观察得出N12160合金适宜热加工区域的变形参数为:ε=0.02～0.6s~(-1),T=1000℃～1080℃和■=0.2～2s~(-1),T=1080℃～1200℃。     

S32750超级双相不锈钢的热变形及组织分析

利用MMS-200热模拟实验机,对S32750超级双相不锈钢在温度为1 000～1 150℃,应变速率为0.01～10 s-1的条件下进行了单道次压缩实验,测定了真应力-真应变曲线,对热变形组织进行了分析.实验结果表明:当变形温度一定时,峰值应力随着应变速率的增加而增加.提高热变形温度,降低应变速率,可以促进奥氏体动态再结晶的发生.根据热变形方程计算得到压缩变形时的热变形激活能Q=460 kJ/mol.在相应的变形条件下,获得了S32750超级双相不锈钢热变形过程中峰值应力与Z参数的关系式.     

均匀化后冷却方式对7050铝合金热压缩流变行为的影响

利用GIeeble-1500热模拟机在变形温度为300-450℃、应变速率为0.001-1.0s-1的条件下,对均匀化后经快速水冷和慢速随炉冷却这2种不同冷却方式的7050铝合金样品进行高温等温压缩实验,研究该合金的热压缩变形流变行为.结果表明:合金流变应力不仅随变形温度的降低和应变速率的升高而增加,而且随均匀化后淬火冷却速度的增加而显著升高;均匀化后水淬样品中合金元素过饱和固溶于基体内,变形过程中第二相析出并明显粗化;快速水冷样品的热形变表观激活能为224.9 kJ/mol,而慢速随炉冷却样品的热形变表观激活能为144.6 kJ/mol;热压缩变形流变应力的差别随形变温度的升高而降低;在高温低应变速率下,应力-应变曲线出现锯齿形波动,呈不连续动态再结晶特征;7050铝合金高温塑性变形时的流变行为可用包含Arrhenius项参数Z的双曲正弦函数描述.     

Ti62421s钛合金的热变形行为及加工图

在变形温度为900～1060℃和应变速率为0.001～10s-1条件下,对Ti62421s合金进行变形量为60％的热压缩变形,以研究Ti62421s合金的热压缩流变应力行为.研究温度与应变速率对Ti62421s热变形流变应力的影响,建立Ti62421s合金热变形流变应力的本构方程和加工图.研究结果表明:合金在热压缩过程中,流变应力随着应变的增大而增加,达到峰值应力后逐渐趋于平稳:当在高应变速率(10s-1)下变形时,出现不连续屈服现象:应力峰值随应变速率的增大而增大,随温度的升高而呈减小趋势:合金最佳变形工艺参数为:温度θ=980℃,应变速率(ε)=0.01～0.1s-1.     

铸态高强铝合金热变形流变应力行为的研究

文中采用热力模拟试验方法对新型铸态高强铝合金试样进行了热压缩实验,研究了新型高强铝合金在变形温度为300~420℃、应变速率为0.01~1 s-1条件下压缩变形程度达到50%的流变应力变化规律。研究表明,该合金热变形应力—应变曲线呈现动态回复型曲线;流变应力随变形温度的升高而降低,随应变速率的增大而增大;热变形激活能为269.985 k J/mol,应力指数为7.009 7。     

800H合金热变形行为研究

通过高温单道次压缩实验,研究800H合金在变形温度850～1 050℃和应变速率0.01～10 s-1条件下的热变形行为和微观组织变化.根据单道次压缩实验数据,绘制了不同变形条件下的800H合金真应力-真应变曲线,通过非线性回归建立了流变应力数学模型;通过线性回归建立了不同温度区间内热变形本构方程.分析了热变形条件对合金微观组织的影响,结果表明:动态再结晶更有可能发生在低应变速率和高变形温度的变形条件下;当变形温度低于950℃时,沿晶界析出的Cr23C6粒子对动态再结晶的发生有一定的抑制作用.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.